Metal corner bead



D. J. BRIGGS ET AL METAL CORNER BEAD March 3, 1942.

Filed Jan. 19, 1959 Patented Mar. 3, 1942 UNITED STTES TENT ()FFICE METAL CORNER BEAD tion of Michigan Application January 19, 15339,v Serial No. 251,768

4 Claims.

Our invention relates to improvements in corner beads formed from flat sheet metal and the objects of our improvements are:

First, to provide a corner bead of simple and economical construction which can be easily bent to conform to concave and convex curves without mechanical alteration of the corner bead;

Second, to provide such a flexible corner bead without sacrificing the strength and protection which is aiforded by continuous attaching flanges;

Third, to provide a corner bead adapted to the surface of plasterboard, sheetrock, or like processed wallboard material prepared in sheets and possessing flexibility and the protective. ad-

vantages of corner beads designed for lath and plaster construction;

Fourth, to provide in a corner bead a system of continuous, but serrated, flanges wherein the serrations are arranged directly opposite to each other, such serrations providing flexibility and affording indentures for the retention of adhesive cement or other finishing material; and

Fifth, to provide a corner bead with a wire member inserted in the bead of the structure for the purpose of enhancing flexibility, adding strength, and facilitating handling of the corner bead by workmen.

In the present state of the art of making corner beads it is customary to design them for use with lath-and-plaster building construction. Under this system of building construction the corner bead is attached, through the use of nails, to the surface of wood lath or the stud and then approximately three-eighths of an inch of plaster is applied. Because of this application of plaster, an ordinary corner bead can be formed out of relatively heavy gauge sheet metal and where it is necessary to apply a continuous flange type of corner bead to curves the workman mustresort to mechanical alteration of the corner bead. It is the custom to notch or otherwise alter the head when it is to be applied to an arch. This operation is, of necessity, troublesome and time consuming and frequently fails to give desired curvatures and workmen employ a variety of methods to accomplish the bending required. This is not so objectionable in lath-and-plaster building construction since any defect in workmanship is easily covered by the three-eighths inch application of plaster. Where corner beads designed for use in the lath-and-plaster type of building construction do not have continuous flanges, but have separated flanges spaced at regular intervals or alternately spaced at regular intervals, in order to provide flexibility, the

strength and protection afforded by a system of continuous flangesare absent. When such corner beads are used, the portions of the wall corner surface between the spaced flanges are particularly vulnerable.

In the construction of corner beads designed for application to the surface of plasterboard, sheetrock, and like processed wallboard prepared in sheets several. conditions are encountered which are not present in lath-and-plaster construction. Since the corner bead is attached to the surface of the wall material and a comparatively thin coating of cement or other finishing material is applied, the gauge of the sheet metal must be reduced as much as possible consistent with strength requirements. The diameter of the bead portion of the corner bead must be much less than in corner beads designed for lathand-plaster construction. The flanges must be designed to provide, in conjunction with the wall surface, an arrangement of indentures which will efiiciently retain the thin coating of cement that is applied over the corner bead and aid in forming a crack-resistent finished wall surface. Because of the use of a lighter gauge of sheet metal and the general reduction in dimensions, Strength. must be provided through design. Insofar as our knowledge extends, no existing type of corner bead, whether primarily designed for surface application or foruse in lath-and-plaster building construction, provides a satisfactory means of finishing or protecting a jointure of two sheets of plasterboard or similar prefabricated wall surface material. Because of the essential differences which exist between lath-andplaster and prepared sheet wall construction, corner beads for the former system of construction and those for the latter system constitute two distinct classes of corner beads and neither can be adapted, without substantial alteration, to the system of construction for which it was not originally designed.

Our present invention provides a corner bead which can be satisfactorily applied to the surface of plasterboard, sheetrock, and like processed wallboard prepared in sheets and which makes possible a more versatile degree of application than is now provided by any existing type of corner bead designed for application to thesurface of such prepared wall materials or by any existing type of corner bead designed for use in lath-and-plaster construction if amenable to adaptation to surface application to plasterboard, sheetrock, or like processed wallboard prepared in sheets. The invention therefore con sists of the peculiar construction, arrangement, and combination of elements hereinafter set forth.

In the drawing, consisting of one sheet and forming a part hereof:

Figure 1 is a perspective detail of a fragmentary portion of our invention.

Figure 2 is a side perspective of a fragmentary portion of the invention.

Figure 3 is a cross sectional view on line 55 of Figure 2.

Figure 4 is a fragmentary view of the invention as applied to a Spanish type arch.

The corner bead consists essentially of a continuous strip of sheet metal bent or drawn to form at its center a tube or bead 3. From the seam of bead 3 two sections or flanges 2 extend outward forming an angle of 90 degrees or less, preferably slightly less. These flanges 2 are provided with nail holes I, the corner bead being affixed to the surface of the plasterboard, sheetrock, or like prefabricated wallboard material prepared in sheets by means of nails. A Wire 4, possessing a suitable degree of resiliency, is firmly secured in the bead 3. Wire 4 is an essential element in the preferred method of construction, for reasons hereinafter set forth, but wire 4 may be eliminated in an alternate method of construction. In applying the corner bead, flanges 2 straddle the corner of the wall to be finished and protected and are aflixed to the wall by nails driven through the holes I. In applying the corner bead to any concave or convex curve wall opening, it is placed in position in the same manner as specified for the ordinary vertical or horizontal wall corner; during this process bead 3 and wire 4 flex to conform to the line of the curve and the distance between the serrations in the flanges 2 contract or expand. If, after the corner bead has been applied to a vertical or horizontal corner in the manner above outlined, a straight-edge reveals an untrue line in the corner to which the corner bead is attached, a reasonable degree of correction can be accomplished by pressure applied to the right or left of bead 3. This degree of correction is made possible by the wire 4 in bead 3 and the general constructional design of the invention. After the corner bead has been secured in position and the corrections in alignment, if any, have been made, the usual practice is to apply successive layers of cement or similar finishing material. This cement or finishing material is applied beginning six to eight inches from the bead, in this instance bead 3, and tapering to the outward extending height of the bead. When the flanges 2 are secured to the wall surface the triangular spaces formed between the serrations of the flanges 2 constitute a series of indentures which serve to effectively retain the cement or other finishing material applied over the corner bead and prevent surface cracks. The flanges 2, as shown in Figure l, are regularly serrated for the purpose of forming, in conjunction with the wall surface, the indentures mentioned. The serrations in the flanges 2, together with the wire 4, also permit flexing the corner bead to conform to concave and convex curves Without mechanical alteration of the corner bead. Wire 4 gives added stability to the bead 3 and prevents the breaking of the corner bead in the flexing process. In the alternate method of construction, wherein wire 4 is eliminated, the aforesaid stability and flexibility are sacrificed to some degree; hence this method is not as satisfactory as the preferred method of construction heretofore described. The flanges 2 form an angle of degrees or less, preferably less, to make possible easy application and close fitting without extensive manual adjustment of the serrations in the flanges 2. The serrations in the flanges 2 have their bases a short distance from the starting point of the flanges 2 at the seam of bead 3, as is shown in Figures 1 and 2. Figure 4, being reduced in scale, of necessity, does not adequately indicate this distance. The effect of this arrangement of the serrations is to provide continuous, but serrated, flanges 2. Although the foregoing is the preferred method of constructing the serrated flanges 2 of our invention, an alter nate form of construction provides a series of abutting serrated flanges having bases starting at the-seam of bead 3. The wire 4 and the peculiar design of the flanges 2, in addition to providing flexibility not present in existing types of corner beads for application to the surface of the prefabricated wall materials heretofore mentioned, compensate for the required reduction in the dimensionsof the flanges and beads of corner beads designed for surface application.

What we claim is:

1. In a corner bead, an arrangement of two continuous flanges, triangular in shape and forming a continuous serration, contractible and expansible to conform to concave and convex curves without alteration or distortion, extending angularly from a'flexible bead, applicable to the surface of prefabricated wall material, substantially as described.

2. A device of the class described comprising a flexible bead, bendable to conform to concave and convex curves without alteration or distortion, housing therein a pliable wire, with two continuous flanges, regularly serrated, extending angularly therefrom.

3. A device of the class described comprising a corner protective means applicable to the surface of prefabricated wall material and bendable to conform to concave and convex curves without alteration or distortion and having a bead, housing therein a pliable wire, withtwo continuous flanges, regularly serrated and regularly perforated for the insertion of attaching means, extending angularly from said bead.

4. A device of the class described comprising a means of finishing and protecting corners formed by the jointure of two sheets of prefabricated wall surface material, applicable to the surface of said wall material and bendable to conform to concave and convex curves without alteration or distortion and having a flexible bead, housing therein a pliable wire, with an arrangement of two continuous flanges, regularly serrated and regularly perforated, extending angularly from said bead.

DAVY J. BRIGGS. FRED DE NIO, JR. 

